1. Field of the Invention
The present invention relates to an apparatus and method for providing substantially uniform radiation of a three-dimensional object with at least one curved surface. More particularly, the present invention pertains to the aforementioned apparatus and method wherein a substantially uniform high level of peak irradiance is projected onto the at least one curved surface to efficiently treat the surface such as, for example, to perform Ultraviolet (UV) curing.
2. Description of the Prior Art
Various manufacturing processes include treating elongated curved object surfaces by irradiating the surfaces with, for example, UV or other radiation. The radiation treatment may be related to curing, purification, disinfection, advance oxidation or some other procedure. By way of example, in some printing processes, a printed pattern is cured by irradiating the pattern. Obtaining a high quality, uniform product requires irradiating a two-dimensional substantially uniform high level of radiation over the surface area of the at least one curved surface which has been coated with a coating requiring irradiating thereof. Otherwise irregularities in the finished product may result.
Existing devices for irradiating objects with radiation, such as UV expose a central area of an irradiated surface to more radiation than edge areas of the irradiated surface. The areas of high irradiation may receive more than the desired level, which can possibly cause damage, while the areas of low irradiation may be under treated.
Various techniques have been used to control the uniformity of irradiation of planar target surfaces as, for example, described in U.S. Pat. Nos. 4,010,374, 4,276,479 and 4,348,015.
United States Published Patent Application No. US 2003/0206399 A1, published Nov. 6, 2003, describes a reflector assembly for UV curing of curved objects such as glass bottles. UV light sources project light to reflectors, which redirect the ultraviolet light from parallel to the axes of the bottles to a direction perpendicular to the axes of the bottles. This permits UV to be applied to the surface of each of the glass bottles to insure that new printing is substantially completely cured. The light from the light source, which is funneled in a direction parallel to the longitudinal axes of the bottles and reflected orthogonally to the longitudinal axes to irradiate the bottles, can result in non-uniform distribution of irradiance on the bottles and non-uniform absorbance of energy thereon.